Monday, 31 March 2014

The A - Z of Sports Vision - Watch The Ball

In the recent 6 Nations rugby there were some classic examples of players knocking the ball on because they had taken their eyes off the ball, usually because they are distracted by a player about to tackle them. But then in football, players are often accused of “ball watching”, when they are so concentrated on the ball that they don’t notice that a player has been left unmarked.
But if that’s confusing, you would think that the requirement to watch the ball in sports such as tennis or cricket would be sacrosanct. However, numerous studies have shown that this isn’t exactly the case: the ball is actually travelling too fast to do this. One of the first was Land & Mcleod (2000) who found that elite batsmen followed the ball for a while before switching their vision to where they predicted the ball would bounce, and then tracking the ball from there until they hit the ball with their bat. Some batsmen, however, are more elite than others. A recent study (Mann, Spratford & Abernethy, 2013) studied two batsmen who had played more than 70 Tests matches, averaging over 45 (I suspect one of them might have been Matthew Hayden), as well as two club-level cricketers. They batted against a ball-projection machine that displayed a life-sized video projection of a bowler in his run up. At the moment of ball release a ball was actually released through a hole in the screen. The participants wore an eye-tracking device that the direction of the head and gaze when batting. They found that the elite batsmen tended to keep their gaze either in alignment with, or ahead of the ball. In contrast, the club batsmen were more likely to have their gaze either in alignment with or behind the ball. The latter only had their gaze ahead of the ball for short-pitched deliveries, and only then for a short period of time after the ball had bounced and before they made contact with the bat. On average the elite batsmen directed their gaze further ahead of the ball, and for a longer time, than the club players. In particular, elite players directed their gaze ahead of the ball immediately prior to hitting it with their bat, whereas club players tended to be behind the ball at this crucial time. Elite batsmen were found to couple their head movement more closely to the movement of the ball, especially as it got nearer to them. They also moved their gaze further in advance of their head direction. In other words, the elite batsmen closely aligned their head with the direction of the ball, whereas club-level batsmen more closely aligned their eyes with the ball. Sometimes the elite batsmen would have their gaze so far in advance of the ball that the image of the ball would be in their peripheral vision; but they still managed to keep their head aligned with the ball. The authors liken this to using a miner’s torch on your head to keep a spotlight on a moving object. Whereas Land & McLeod had found that better players made one saccade (where the eyes jump to a new location) to where they expected the ball to bounce, and then tracked the ball to contact, these elite players made a second saccade after the bounce of the ball to where they anticipated the contact would be. This second saccade was made for balls that were either short of a length or on a good length. Club players were much less likely to make a second saccade. All players made just one saccade when the ball was of a full length, but the elite players’ saccade took them past the bounce point to the predicted contact point, whereas that of the club players tended to lag behind the contact point. The coupling of the head to the movement of the ball seems to help the elite batsmen predict where the contact point will be. Crucially, this meant that the elite players were more likely to have a sharp focus on the contact between bat and ball compared with the club players. “Keep your head aligned with the ball” would not be a particularly helpful instruction to aspiring young batsmen, even though it seems to be what’s required at an elite level. I think the best coaches could advise would be to watch the bowler’s action carefully (so you can predict where the ball will bounce and what type of delivery it will be), carefully note where the ball pitches, and try and watch the contact point between bat and ball. David Donner

Monday, 3 March 2014

The A - Z of Sports Vision - Visualisation (and video)

Visualisation should be an essential part of any athlete’s training because it can have a profound effect on performance. In fact, most athletes probably do use visualisation, but they don’t necessarily use it very effectively, and may even be using it in a way that negatively affects their performance. For instance, if you replay a mistake you’ve made over and over in your head, it’s like practicing making errors so makes it more likely that you’ll make the same mistake again. The first mistake people make is to think that visualisation is just about vision – what you’ve seen. That’s partly because visualisation is something of a misnomer: “mental rehearsal” would be a better term (except I’d have to come up with another “V”) because it allows you to use all your senses to recreate the activity, and that’s when it becomes really powerful. To give you an idea just how powerful it can be, 10 volunteers took part in mental workouts 5 times a week for 12 weeks in which they had to imagine pushing against a heavy object (Ranganathan et al, 2003). They actually increased their bicep muscle strength by 13.5%, and maintained this increase for three months after the training stopped. A famous imagery experiment involved wiring electrodes to the legs of an Alpine skier to test out the notion that vivid imagery produces electrical activity within the muscles similar to the electrical impulses produced during actual movement (Suinn 1980). The experiment showed that when the skier was sitting down, simply thinking of skiing downhill, similar electrical patterns were found in the muscles as if he had actually been skiing. By imaging or visualising yourself playing sport, the muscles you would use to physically perform the task are stimulated at a very low level. This gentle muscle activation is not strong enough to produce actual movements, but it establishes a blueprint for that particular movement or situation. By visualising a successful performance, it makes it more likely that you will produce the correct response while under pressure. The subconscious brain can’t easily distinguish the difference between imagination and reality the way your conscious brain does. This is why dreams can sometimes feel really lifelike. So visualisation is just another form of practice, and it’s much better to practise doing things well than doing them badly. Visualisation can be used for learning new skills, strategies and routines, but it can also be used to motivate, control stress and boost confidence. It can be used to improve concentration and to recover from injury, as well as dealing with errors and stressful situations. It’s also been found that athletes instructed to imagine successfully performing a task voluntarily practised longer than others. You can visualise your performance as you normally see it, or as it might look on TV. Video can help athletes visualise their performance in real time. I’m currently videoing some rugby players in training. The idea is to pick out some of their best bits, and maybe set them to music, so players can use this as part of their pre-match preparation and general confidence booster. It will be interesting to see how it works. David Donner